Keel Cooled Air Conditioning

[zboss]

So this is interesting...

USA and Canada - AC, Aircondition för båtar i medelhavet,environmentally friendly aircondition, Låg energi

[MartinMV]

Originally Posted by zboss

So this is interesting...

USA and Canada - AC, Aircondition för båtar i medelhavet,environmentally friendly aircondition, Låg energi

Yes, That's interesting. Thank you for posting the link.
Could work at anchor.

Also probably easily done as do it yourself project scaled to ones needs.
It just a 12V pump with a heatexchanger and water in and out.

[hellosailor]

What could be unmarketable about MORE custom installation requiring MORE parts, MORE connections, MORE installation labor, and oh yeah, critical parts MORE vulnerable to damage from grounding? As well as MORE places the system could leak and requiring MORE refrigerant.

Yes, water is something like 14x more efficient at removing heat from the system so in theory water-cooled is a vastly superior system.

But that's why the inefficient VW Beetle's were such a success, they never had problems with leaking water pumps or radiators or cooling issues from all that good stuff. They just ate a little more gas, had a little less power, no one ever asked.

And the statisticians like to remind the engineers, every time you double the number of parts, you quadruple the failure rate. It goes up by multiples, not simple addition.

Now, if you're trying to DIY or willing to simply pay for the most efficient system you can get, and you can get competent help to install it...different criteria.

[redsky49]

For the record, we are in a marina in North Florida. A.C. runs constantly and strainer hasn't been cleaned in six months, though needing it now. As they say, it all deepends.

[hellosailor]

Six months and no plastic bags in the strainer? Wow, the fines for littering in that county must be intense. (G)

[Singleprop]

My air conditioning system is keel cooled, it's a 60.000 BTU unit with 2 compressors.

I only use 1 compressor at a time as I'm running a full electric galley, ovens, fans and ventilators running full time - so power management is vital...

In the height of the summer the sea water temperature is around 87F, the keel cooler inlet temperature is 104F and the return temperature is 96F...the keel cooler pipes have not been cleaned for some time so I would expect the return temperature to be around 90-93F with clean pipes.

What's the Delta-T for a raw water cooled system anyway?

I have approximately 60 feet of 4" halfpipe welded onto the hull, with some restrictions such as 2 x 180 degree turns and 2 x 90 turns and also a large strainer....I don't know if this keel cooling system is correctly sized as I would have expected a larger Delta-T between inlet and return - but at least it is cooling...I'll remove the strainer basket one day to see if this improves the Delta-T..

In any case - the keel cooling concept works.

A simple way to check if this works on an existing raw water cooled system will be to find a long hose, connect to the inlet/outlet, then toss the hose overboard and see what happens...

[rourkeh]

"Is there a reason why keel cooled air conditioning systems are not more popular? "

Yes they do not work.....

[Sailmonkey]

Originally Posted by rourkeh

"Is there a reason why keel cooled air conditioning systems are not more popular? "



Yes they do not work.....

They work really well on commercial vessels that are almost always in motion. Where they don’t do so well is when vessels are stationary in shallow stagnant water. IE tied to a dock in an area with little tidal flow and shallow water.

[redsky49]

"What's the Delta-T for a raw water-cooled system anyway?"

Depends. What is the flow rate? 3 gpm per ton of cooling would be a good starting place. [Typical commercial systems are frequently 2.4 gpm per ton, though under more controlled conditions]. In other words, between 10 and 16 degrees F would be a logical range.


"They work really well on commercial vessels that are almost always in motion. Where they don’t do so well is when vessels are stationary in shallow stagnant water. IE tied to a dock in an area with little tidal flow and shallow water."

Not so. The absence of flow around a keel cooler may affect the efficiency to a small degree (for example, a stationary vessel may develop more fouling on the exterior of the keel cooler, compromising heat transfer). The ambient conditions are the true determiner of performance. The warmer the seawater, the lower the performance. This is a somewhat simplistic response.



To counter this, increase the condenser water (seawater) flow.


For peak performance and efficiency, all parameters must be considered.